I would respectfully disagree that it is a "fine new identity." It's more whimsical and fun, but I think many of the people writing here would assert that its identity is not very targeted. Again, I think Tomorrowland is fun, but for purists who want a discernible identity, it's a bit of a challenge. However, if you want a Tomorrowland that simply contrasts with the jungley Adventureland, or the princessey Fantasyland, or the rootin' tootin' Forntierland, or the patriotic Liberty Square, or the nostalgic Main Street, it does a great job.
I think a potential fatal flaw of Tomorrowland would be for it to take itself too seriously. It certainly does not, which is good. Future World, on the other hand, should have fun elements, but it should also have a more serious and imposing tone. Yes, it should inspire and delight, but it should not drift over to be as goofy and carefree as Tomorrowland.
By the way, that's why the old TTA narration was so delightful. It actually seemed to try to take itself seriously, but obviously it wasn't. Genius. Just like Buzz Lightyear says he is saving the universe from Emperor Zerg in Sector 9, we all know that it's a cartoon adventure. That's why it works. Compare that to Mission Space, which tries to be a serious voyage to Mars with a slight air of intimidation.
If Future World ever becomes overtly goofy and whimsical, we will have lost something great. Which is also why, perhaps, so many people are so appalled by Nemo and the current version of Figment. They are a ridiculous breach of the inspiration and wonder that should be Future World. In some ways, Space Mountain fits far better in Future World than in Tomorrowland, but a touch of wonder, intimidation and seriousness in Tomorrowland keeps the thrill-seekers happy. It's not a cohesive element of Tomorrowland, but it does a great job of giving that little extra jolt to families who want it, and gives a break from the cotton candy of the other attractions. By contrast, Nemo and the current Figment are just out place in Future World. They're like a popcorn popper in the corner of a fine French restaurant.